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Need exhaust manifold stud for repair.....

bandit67

bandit67

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Guys, my machinist kinda left me hanging on this one. Took in a set of bb heads for rework and ask him to repair a broken off exhaust stud , one on the end in the water jacket. He only drilled out the broken stud.Loading up everything I forgot to check, so just found it on assembly day. So, do they make an one sided oversize stud, maybe something like a 7/16 by 3/8 fine thread. I am concerned putting in a heli coil with a stock size stud may be hard to prevent a coolant leak. Want to fix this now before getting the engine in the car. thanks....
 
Heli coil is the best repair. Do it then put a stud in like you would any other bb head with a little sealer. Done.
 
yella71 said:
Heli coil is the best repair. Do it then put a stud in like you would any other bb head with a little sealer. Done.
Click to expand...
I second this repair. This is exactly how I repair the threads that protrude into a water jacket. If you really want to get fancy install a Time Sert and sealer and it will be the last thread repair for that hole ever unless you bugger it up again.
 
A heli coil should seal up alright, if your really against it then check out McMaster Kart, should be able to find an adapter stud to take care of it.
 
My machinist put a heli coil in mine and said be sure to use a good sealer for the stud. This is very common.
 
I am here to tell you that the likelihood of a "Heli-Coil" sealing a stud into a water-jacket is NIL. The problem is that there are too many leak paths with the Heli-Coil. I have tried this route a few times (3 for me), and they wouldn't stop leaking. I have since gone to using Time-Serts regularly. I would recommend either a regular Time-Sert, or if the hole they drilled is too large, a Big-Sert. The Big-Sert is designed to repair a hole that is larger than it should be to go back to the original size. If a Time-Sert gets damaged, they can be drilled to remove the tension holding it in place, removed, and a new Time-Sert installed.
 
I am looking into these Time Serts. I have put in several heli coils from a kit purchased and had great results .....but not in a water jacket. It just appears way to pourus to hold back pressurized hot coolant to me....even with the best sealant I could find. Will check with my NAPA store here first before I order some online. The drill needed for a 3/8 is a 21/64 and it appeared my machinest used a bit two sizes bigger. Is the drill size needed for the TimeSerts the same used for heli coils or bigger.....thanks....
 
bandit67 said:
Guys, my machinist kinda left me hanging on this one. Took in a set of bb heads for rework and ask him to repair a broken off exhaust stud , one on the end in the water jacket. He only drilled out the broken stud.Loading up everything I forgot to check, so just found it on assembly day. So, do they make an one sided oversize stud, maybe something like a 7/16 by 3/8 fine thread. I am concerned putting in a heli coil with a stock size stud may be hard to prevent a coolant leak. Want to fix this now before getting the engine in the car. thanks....
Click to expand...
Somebody must make them - it's not uncommon in the metric world, they're called reducing studs. Maybe you need to make your own on a mini lathe.
s-l300.jpg
 
Ok, I found a "reducing stud" , 7/16-14 by 3/8-24 the same length as stock studs. The drill for the 7/16 is a "W", which is just a few thousandths different from whats needed for a Time Sert . The Time Sert 3/8 kit is $80 bucks. I am thinking that in using the reducing stud would eliminate one possible source for a coolant leak. Two sources with the Sert verses only one with the stud. What would you do.

IMG_0252.jpg IMG_0252.jpg
 
bandit67 said:
Ok, I found a "reducing stud" , 7/16-14 by 3/8-24 the same length as stock studs. The drill for the 7/16 is a "W", which is just a few thousandths different from whats needed for a Time Sert . The Time Sert 3/8 kit is $80 bucks. I am thinking that in using the reducing stud would eliminate one possible source for a coolant leak. Two sources with the Sert verses only one with the stud. What would you do.

View attachment 1097459 View attachment 1097462
Click to expand...
Without a question, the time-Sert, but I guess I am biased towards fixing it correctly. There are NO leak paths with a Time-Sert when installed correctly. If you are concerned, just use a little red Loc-Tite on the insert. On the upside, you have the ability to fix any 3/8"-16 bolt hole on your stuff from now on.
 
69Bee said:
I am here to tell you that the likelihood of a "Heli-Coil" sealing a stud into a water-jacket is NIL. The problem is that there are too many leak paths with the Heli-Coil. I have tried this route a few times (3 for me), and they wouldn't stop leaking. I have since gone to using Time-Serts regularly. I would recommend either a regular Time-Sert, or if the hole they drilled is too large, a Big-Sert. The Big-Sert is designed to repair a hole that is larger than it should be to go back to the original size. If a Time-Sert gets damaged, they can be drilled to remove the tension holding it in place, removed, and a new Time-Sert installed.
Click to expand...

Butter that sucker with aviation gasket sealer. Let her sit for a week, and boom goes the dynamite.
 
Durandal25 said:
Butter that sucker with aviation gasket sealer. Let her sit for a week, and boom goes the dynamite.
Click to expand...
All I can say is good luck. I used Permatex #2 non hardening sealer, ARP Teflon thread sealer, etc and nothing worked.

ps.. I repair a LOT of threads, right Jim... :thumbsup:
 
My Time Sert kit arrived today and it was real simple to get insert and stud installed. Got it sealed and feel it went well and hopefully no problems down the road. Waiting on new oil pan from 440 source and then will oil prime the motor. Got an engine run stand that hopefully can be modified for the 440 and then do the cam break in run. thanks all....
 
Guys, I obtained a used motor 440 from a drag racer downsizing his garage clutter. On closer inspection I found a least 8 heli coils installed where exhaust studs would have been. I assume they were removed to assist with the install/removal of headers. In looking at the coils I would not trust any of them not to leak. So, how does one remove old , severely worn heli coils to replace them with Time Serts. And what sealant have y'all had good luck with.
 
Heli-Coil has a removal tool, but you can use a pick/screwdriver/etc.. to work out the top of the Heli-coil, then grab it with pliers or side cutters and just yank it out. It will un-spiral and come right out. The previously tapped hole should be the same as the Heli-coil, but you can use the Time-Sert tap to chase the hole, and continue as usual.
 
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